Open Current Sense Detection in Multiphase Buck Regulators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multiphase and parallel converter type voltage regulators often fail to detect open current sense lines, leading to potential catastrophic failures and exothermic events due to operating beyond component limits, as faulty current sense information is undetected, causing continued operation with incorrect data.
Innovation Solution
A multiphase voltage regulator design with a current sense interface and pullup circuits, where each current sense circuit has a separate line with a pullup circuit of higher impedance, allowing the controller to detect open faults by measuring voltage changes, enabling fault detection and response mechanisms such as disabling affected power stages and setting status registers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional current sense circuits are used without pullup circuits, then the device complexity is lower, but the reliability deteriorates because open current sense lines cannot be detected
Solution Approach 1:
The pullup circuits are connected to current sense interface lines before normal operation begins, establishing a known voltage state that enables detection of open faults. The fault detection circuit continuously monitors these lines during startup and operation to identify open conditions before they cause catastrophic failures.
Solution Approach 2:
Pullup circuits serve as intermediary components between the current sense circuits and the controller. They provide a reference voltage state on the interface lines and enable the fault detection circuit to distinguish between normal operating conditions and open faults through voltage level monitoring.
2Object-affected harmful factors
If the voltage regulator operates without open fault detection, then the device complexity is lower, but the object-affected harmful factors increase due to potential catastrophic failures and exothermic events
Solution Approach 1:
The fault detection circuit proactively identifies open current sense line conditions before they can lead to catastrophic failures. By detecting the abnormal voltage state caused by open faults, the system can take preventive action to disable affected power stages before operating beyond component limits.
Solution Approach 2:
The pullup circuits and fault detection circuitry create a feedback mechanism that continuously monitors the health of current sense interface lines. When an open fault is detected through voltage level changes, the system receives feedback to disable the affected power stage, preventing harmful operating conditions.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A multiphase voltage regulator includes a plurality of power stages (108), a plurality of current sense circuits (118), a controller (104) and a current sense interface (120) running between the controller (104) and one or more of the current sense circuits (118). The current sense interface (120) includes a separate line (122) for each current sense circuit (118) coupled to the current sense interface (120) and which is configured to support single-ended or differential current sense. The regulator also includes a plurality of pullup circuits (124), each of which is connected to one of the current sense interface lines (122) and has a higher impedance than the line to which it is connected. A fault detection circuit (126) of the controller determines if an individual one of the current sense interface lines (122) has an open fault, based on the pullup circuit (124) connected to the line with the open fault pulling up the voltage on the line (122) by more than a predetermined amount.